Bulletin - United States National Museum - Smithsonian Institution

172 BULLETIN 91, UNITED STATES NATIONAL MUSEUM.
DISCOPSIS ALFREDENSIS, new species.
Plate 31, figa. 1, 2, 3.
Shell small, sublenticular, white, excepting the nuclear whorls,
which are pale chestnut brown. Nuclear whorls two, small, wellrounded,
forming an elevated helicoid spire with strongly impressed
suture. Postnuclear whorls very wide, moderately rounded, marked
by decidedly retractive, wavy riblets, which, on the last half of the
last volution, become irregular and strongly wavy. These riblets
are about one-fourth as wide as the shallow concave spaces that
separate them. The latter are crossed by spiral threads which are
almost equal to the axial riblets in strength. There are about 20
of these between the summit and the periphery on the last turn.
On the last half of the last turn these also become decidedly irregular
and wavy, and the entire sculpture of this portion of the shell assumes
a crinkly appearance. Periphery strongly angulated. Base with
a very broad funnel-shaped umbilicus, which occupies fully half the
space, and which is bordered by a tumid area at its exterior limit;
the space between this tumid area and the peripheral angle is slightly
concave. The entire surface of the base is marked by the continuation
of the axial riblets, which are somewhat sinuous and become
closer approximated here than on the spire. These riblets extend
strongly into the umbilicus. The spaces between the riblets are
marked by fine spiral striations. Aperture very large, very oblique,
the basal and outer lip forming a decided angle at the periphery;
posterior angle obtuse; outer Up decidedly patulous, thin, showing
the external sculpture within; inner lip curved, thin, slightly reflected,
the outer and the inner lip almost approaching each other on the
parietal wall.
The type and another specimen of this species, Cat. No. 250533,
U.S.N.M., come from Port Alfred (Coll. No. 1406). The type has 1.1
postnuclear whorls, and measures: Greater diameter, 1.8 mm.
DISCOPSIS AFRICANA, new species.
Plate 33, figs. 5, 6, 7.
Shell small, discoid, bluish white. Nuclear whorls two, well
rounded, smooth, forming a depressed helicoid spire with strongly
impressed sutures. Postnuclear whorls one and one-fifth, expand-
ing rapidly in size, marked with a strong, lamellar, wavy, peripheral
keel, which has a ruffle-like appearance. The space between the
summit and this keel is marked with spiral cords, of which 17 are
apparent on the outside of the outer lip. Of these, the fourth below
the summit forms a strong shoulder, the fourth, sixth, ninth, eleventh,
thirteenth, and fifteenth being stronger than the rest, while the
remainder are of about equal strength. The space between the one